Rotating generating tool for automatic lathes



y 0, 1929. J. J. THACHER 22, 0

ROTATING GENERATING TOOL FOR AUTOMATIC LATHES Filed Nov. 1, 1924 2 Sheets-Sheet 1 yy; INVENTDE W//w Z A TTURNEY y 0, 1929. J. .J. THACHER 1,7225

ROTATING GENERATING TOOL FOR AUTOMATIC LATHES Filed Nov. 1, 1924 2 Sheets-Shiet 2 INVENTOR Patented July 39, 1929.

UNETEE dl' ares Q t me JOHN J. TEACHER, OF EVETI-ZEBSFIELD, CGNNECTICUT, ASSIGNOR TO PRATT & WHIT- I,

HEY COMPANY, OF NEW YORK, 11. 35., A CORPORATION 01 lIEVT- JERSEY;

screams ennsaa'rine EGQL non anrearn'rie LAC-TEES.

Application filed November 1, 1524. Serial 1 To. 747,341).

This invention relates to automatic machines and in particular to an automatic lathe of the type shown in the patent to Muller 1,252,928 granted January 8, 1918. A principal object of the present invention is to provice an automatic lathe of the type above mentioned with a generating tool adapted to be simultaneously rotated and advanced parallelly to the arns of the blanlr.

Another object of the invention is to provide a generating rotatii g tool and actuating mechanism therefor which may be mounted upon the tool carriage usually provided on automatic lathes of this type. feature which enables me to-accomplish the above named objects is that the cutter, or one of them is mounted upon the lower end of a vertical shaft driven through appropriate gearing by another vertical shaft driven from a gear in mesh with a fixed rack.

A further object of the invention is provide a pair of these generating rota g tools preferably of different diameter and adaptedto engage the work at dian'ietrically opposite points, one being adapted to take a roughing cut and the second a finishing cut.

' With these and other objects in view, my invention consists in the features of construction and operation set forth in the following specification and illustrated in the accompanying drawings.

In the accompanying drawings annexed hereto and forming a part of this specification I have shown my invention embodied in an automatic lathe adapted for turning the interrupted cylindrical surface of a twist drill, but it will be understood that the invention can be otherwise embodied and that the drawings are not to be construed as defining or limiting the scope of the invention, the claims appended to this spec fication being relied upon for that purpose.

In the drawings:

Figure 1 is a front elevation of part of an automatic lathe showing the present invention applied thereto. I

2 is a plan view of an automatic lathe provided with the present invention, parts being cut away to show the engagement of the cutters with the work.

Fig. 3 is a side elevation in section of the One I cutters and adjacent parts taken upon line of Fig. 2.

F 3. is a detail plan View showing the locking connection between one of the tool spindles and its driving gear, and

Fig. 4 is a diagrammatic View in plan showing the relative positions of the cutters at the beginning and end of their cutting movement. r

In the above mentioned drawings, 1 have shown but one embodiment of the invention which is now deemed preferable,but it is to be understood that changes and modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

Briefly and in its broadest aspect, my invention comprises the following principal parts which may be mounted on an automatic lathe substantially similar to that shown in the above referred to patent and having a base, blank supporting and rotatmeans, a magazine, an automatic transferring mechanism for the blanks and a tool actuating slide. These parts comprise: First, a supporting head rigidly secured to the tool slide; second, parallel.shaftsthereon; third, cutters mounted upon thelower ends of two of these shafts; fourth, a rack fixed to a part of the base; fifth, a gear meshing with said rack; and sixth, driving connections between said three shafts.

Referring more in detail to the figures of the drawings, the automatic lathe comprises a base 10, a headstock 11 having a work rotating spindle 12 therein, and 'a tailstock 13, its spindle 14 preferably being adapted to be automatically actuated. stock spindle 12 is a chuck 15 preferably of the floating type. A magazine v16 is provided in rear of thebase 10, transfer arms 17 being adapted to convey a blank A from said magazine 16 into operative position on the headstock andtailstock'spindles 12 and 14. A tool slide 18 adapted to move in a direction parallelwith the axis of the blank A is moved along the base 10 by an actuating slide 19, preferably cam controlled, as shown in the above mentioned patent.

As each of the above referred to mecha nisms is, or may be, similar to those shown in the above mentioned patent, it is not thought that a detailed description thereof V spindle 29.

is necessary. It will be suriicient that these mechanlsms are cont olled relation to each other, so litil'it blank may be mounted in operative position upon the spindles from a position in the magarue tool mounted upon and being moved with the tool slide 18. This mechanism cc prises a support 21 secured detacl; the tool carriage 18 and which pr takes the place of a cross slide usually pro vided on lathes ot this type. By oper of a screw 417, the support 21 may be metoward or from the axis of the blank A. shown clearly in the drawings. the suppoi 21 on its. lower surface is provided with a dovetail projection 22 adapting .3 to R in the corresponding recess provided in the tool carriage 18 for a cross oi usual form.

This support 21 is provided with a vcrti cal driving shaft 23 having a gear 2% at its upper end and a 'ear 25 at its lower end. The 25 at the rower one is in mesh with a rack 26 extending parallelly with the axis of the spindles 13 and 14!; so that it is or stantly. in mesh with the ear 25. fee rack 26 is lined during operation to part 27 detachably secured to the base of the lathe 10. At the upper end of the shatt 23, the gear 24! thereon is in mesh with a second gear 28 at the upper end ot a cu r This spindle 29 carries at lower end a generally circular disc having cutting surfaces formed upon its periphery. This cutter 20. as s iown clearly in h" 2-). is adapted to be quickly removed or placed upon its spindle 29 and prevented from rotating relative to its spindle 29 l? means of a suitable key 30 or othc loc device. Preferably the spindle is provided with a bolt 29 extending through providing; menus L for attaching tie uutter. h nut upon. the threaded lower end of the spindle bolt 29 securely holds the cutter 20 in position on th spindle 29.

As it is frequently desired '0 rotative position of the cutter 2 or correctly positioning its cutting contour tive to the blank being cut means c i vided therefor to the spindle L9 relative to its gear 28. .he gear 28, i r being directly secured to the spindle 29., s

1 mounted upon a suitable sleeve 32. This sleeve 32 1s keyed to the spindle 29 as shown.

The sleeve 32 is provided with a flange havn F i ing notches or teeth 33 cut in its periphery which ma be engaged by a locking tooth 3% held in place upon the gear by means of the screw 35 shown in Fig. 3. means, with the locking tooth 3 removed, s spindle 29 can be rotated without rotatwhen the cutter 20 is osi'aion the gear 28 and spinlocked togetherbymeans of ea i the above that linear t ol carriage 18 in a dithe axis the blank A "riving shaft 23 to rotate mover i he or rection Jaral cause the I la 23 and spindle 2S). '1 otion impart c to the cutter 20 is i i c combined linear and rotative one, t movement being in the direci ow shown in Fig. l. The cut- JV therefore has substantially rolling ovcment alonga line parallel to the aXis the blank bcing' out Preferably the gears and 2S cutter 20=are so proportioned that the cutting suriaces of the cutter 20 do ot have a true rolling movement, but enage the blank A with a slight sl ding ac- That is, the movement or the cutting aces on cutter 2(lrelative to the blank a combined rolling and sliding movement. This slidi movement can, of course, be varied by changing the ratios of gears 2 land 28 and the diameter 01 the cutter 20.

In the present embodimem of the inven tion, two cute ng tools or generally similar shape are provided. described is adapted o the blank A upon the one side. 1 preferably mount a supplemental cutter 40 to engage the blank it upon the opposic Ede of the blank so that t pressure or q k the tools 20 and 10 against the work s i tend to compensate and neutralize earn other. The supplemental cut'i +10 shown most clearly in Fig. 8, is, e s 1 lum 1 til as s own, no erect and ouaenao y moumet upon the lower end or the supplemental cutter spiirdle all. This cutter 420 may be socured to the spindle ll bv means of a suitable key 4.2 and retained thereon by means 1* '.A ...'..1 +,Jl1-v, or a nut n3 engaging e118 threaded iOWGl end of a spindle bolt ell. The upper end of the spindle ll is provided with a sleeve smular to that upon the first cutterspmdle 29 and upon this sleeve is a gear in mesh with the iii-H 28 at the upper end of the a. 4- i, 0 T? i iii-st. (Hotel s1 .ndle 29 means are plOrltlGtl in the form or a locking member as to relatively ad ust the rotative or angular position of thec'i ter 4:0 relative to the gear 45.

it wil ,e i set; rom the above description carriage 18 along that nuwement or me tool the base 10m a direction toward the headst cl:

By these 7 the cu ter spindle 29 by reason of- The cutter 20 above 11 will cause the two cutters 20 and 40 i 27 and enter to roll and slide along the surface of the blank A. It will be understood, of course, that the cutters and may be properly positioned by adjustment of the screw 47 and by providing cutters having the correct diameters.

Preferably I make use of the first cutter 20 of large diameter to rough cut the blankv A and use the supplemental cutter 40 of smaller diameter to engage the blank justafter engagement by the cutter 20 and take a finishing cut. As these cutters 20 and 40 are simultaneously in engagement with the blank, the pressures of neutralize each other. Also on account of the differences in diameter, the cutter 2O having a larger radius of curvature to its periphery cuts slightly in advance of the cutter 40 and therefore may take a roughing cut. lhe cutter 40 has a smaller radius of curvature and therefore may take a small finishing out upon the opposite side of the blank. By adjustment of the cross slide 21 to advance the finishing cutter 40 toward the axis of the work, the same cutters may be employed for slightly different diameters of blanks.

Referring to the diagrammatic figure the operation of the cutters will be clear. Starting with the cutters at the right hand end of the blank, movement of the carriage 18 advances them parallelly along the blank A. Simultaneously the connections from the rack 26 and shaft 23 cause them to rotate in timed relation to the advancing motion. The effect of this combination of motions is to produce a rotary and sliding engagement of the cutting surfaces of the cutter with the blank.

As shown in Fig. 4, the periphery of cutter 20 is so formed that it forms the necked portion a on the blank A. Approximately one half only of its periphery is made use of in one setting of the cutter. For slight variations of blank diameter or to compensate for grinding away of the cutters to resharpen them. adjustments of the, cross slide or support 21 must be made. This requires corresponding adjustment of the rack 26 in its clamping member 27. The rack therefore may be clamped by means of a screw n any transverse position in the member 2 To prevent lengthwise movement of the rack 26, a pin 51 may be driven into the member a recess provided in the rack What I claim is:

1. A metal cutting machine comprising in combination, a base, blank supporting and rotating means thereon, a tool carriage movable parallelly to the axis of rotation of the blank, a rotatable cutting tool on said carriage having its cutting surface upon its periphery, a normally fixed rack, a shaft havthe cutters tend to ing a gear thereon adapted to mesh with said rack, a spindle driven from said shaft and carrying saidcutting tool, and a supplemental spindle carrying a cutting tool and driven from said first cutting tool spindle whereby movement of said carriage simultaneously advances and rotates the cutting tools and simulates a rolling motion thereof.

2. A metal cutting machine comprising in combination, a base, blank supporting and rotating means thereon, a tool carriage movable parallelly to the axis of rotation of the blank, a rotatable cutting tool on said carriage having its cutting surface upon its periphery, a normally fixed rack, a shaft having a gear in mesh with said rack, a spindle for said rotatable cutting tool and gears connecting said shaft and spindle for rotating said cutter spindle whereby move ment of said carriage will simultaneously advance and rotate the cutting tool and simulate a rolling motion thereof.

8. A metal cutting machine comprising in combination, a base, blank supporting and rotating means thereon, a tool carriage mov able parallelly to the axis of rotation of the blank, a rotatable cutting toolon said carriage having its cutting surface upon its periphery, a normally fixed rack, and gear means associated with sald rack for rotating said cutter, a supplementaryrotary cutter disposed upon the opposite side of the blank, a spindle supporting said supplementary cutter, and means to drive said supplementary cutting tool in timed relation to said first cutter, whereby movement of said carriage will simultaneously advance .and rotate the cutting tools and simulate a rolling motion thereof.

4.. A metal cutting machine comprising in combination, a base, blank supporting and rotating means thereon, a tool carriage movable parallelly to the axis of rotation of the blank, a rotatable cutting tool on said oarria'ge having its cutting surface upon its periphery, a normally fixed rack, and gear means associated with said rack for rotating a vertically disposed shaft, a spindle carrying said cutting tool and driven in timed relation to the shaft, a supplementary rotary cutter disposed upon the opposite side of the blank, a vertically disposed spindle supporting said supplementary cutter, and means to drive said supplementary cutting tool in timed relation to said first cutter, whereby movement of said carriage will simultaneously advance and rotate both of said cutting tools and simulate a rolling motion thereof.

signature.

JOHN J. TEACHER. 

